For certain versions of SDL, there will be a x86 folder and a x64 folder inside of the lib folder from the archive. The x86 folder contains the 32bit *.lib files
and the x64 bit folder contains the 64bit versions of the library files. If you're compiling a 32bit program, set the new library directory to the x86 folder and if you're
compiling a 64bit version set the new library directory to the x64 folder. By default Visual Studio compiles in 32bit so if you're not sure how you're compiling, try the 32bit
libraries first. What matters here is not whether you have 32/64bit windows, but what type of program you're compiling.

If you don't see a x86 or x64 folder inside of the lib directory from the archive, just set the lib folder from the archive as the new library directory.

12)In the C/C++ menu under Code Generation, set "Runtime Library" to
Multi-Threaded DLL:

13)Now build. If there are any errors, make sure you didn't skip a step.
Before you can run this SDL application (which does nothing visible) take the SDL.dll from the archive you
downloaded (it should be inside the lib subfolder) and extract it. You're going to put this in the same directory as
your project/exe after you compile it.

Alternatively, you can copy SDL.dll to C:\WINDOWS\SYSTEM32 so your SDL app will find SDL.dll even if it's not in
the same directory. If you're using a 64bit version of Windows, you'll want to put the dll in C:\Windows\SysWOW64.

The problem with this method is if you have multiple SDL apps that use different versions of SDL, you'll have
version conflicts. If you have SDL 1.2.8 in SYSTEM32 when the app uses 1.2.13 you're going to run into problems.
Generally you want to have your SDL.dll in the same directory as your executable developing and you'll
always want to have SDL.dll in the same directory as the exe when distributing your app.

The tutorials use #include "SDL/SDL.h" to include their header files. Simply change it to
#include "SDL.h" to make it work with Visual Studio.

Also, In the archive you just downloaded there's a subfolder called "docs".
It contains the SDL documentation.

I highly recommend that you extract them somewhere and keep it for reference.